Great. First open up both images in Photoshop. Next you'll have to shrink down the yellow image down to about 500 pixels because the flowered image is small.

Drag or copy and paste the flower image on top of the yellow image. In your layers pallete change the setting Normal to Multiply. That makes the top image 'merge' with the background image.

You can remove I Do, Ltd. with some patience I would use the Clone Stamp Tool (hit S on your keyboard) Sample the yellow color in the background by hitting option and click. Next click your mouse and drag over what you want to 'erase' with what you just sampled... If you've used the Stamp tool before this will be straightforward. If not this might take some more explaination. Just let me know.

Are you doing this for fun or do you plan on printing this out or using it on the web? I ask because the flower image is not a high enough resolution to hold up for print.

Make sure you aren't using a copyrighted image if you plan on using this for commercial purposes.

it is essential to find images with the same dimensions or close. In this tutorial that wasn't the case, but that's because my goal here is just to explain how I did this.
OK, lets begin, open the source image. this will be your background Layer, (the layer on which you will put your second image face, if you are confused now don't worry it will all clear up in a moment). Here is the source image I used:
open your first image or any painting.
Now open the second image.

Now take the Polygonal Lasso Tool and cut out face and drag it to the Layer with the painting. Transform the face to fith the face of the painting. Lower the opacity to see throw for easer transform. See the picture below:

Add a Layer Mask to the face and mask with black color to erase the face were you don't want it to show, see picture below:

If there is a face showing from the painting just add a new Layer above the background Layer and clone it with the black background from the painting.
Now, back on the face, open the Curves options and experiment with the values there, I just tweak the blue and the red colors a bit and then open the Selective color option and add very little blue and yellow color's.
Create a new Layer And put it on top in the Layer Palette, take the clone tool and clone the texture from the face of the painting on the new Layer. When you are going to finish that open the Blending Options and on the Default window experiment with the values where it says ''blend if''.
And you are done, here is mine result: